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Leal AS, Hung PY, Chowdhury AS, Liby KT. Retinoid X Receptor agonists as selective modulators of the immune system for the treatment of cancer. Pharmacol Ther 2023; 252:108561. [PMID: 37952906 DOI: 10.1016/j.pharmthera.2023.108561] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Revised: 09/28/2023] [Accepted: 11/06/2023] [Indexed: 11/14/2023]
Abstract
Upon heterodimerizing with other nuclear receptors, retinoid X receptors (RXR) act as ligand-dependent transcription factors, regulating transcription of critical signaling pathways that impact numerous hallmarks of cancer. By controlling both inflammation and immune responses, ligands that activate RXR can modulate the tumor microenvironment. Several small molecule agonists of these essential receptors have been synthesized. Historically, RXR agonists were tested for inhibition of growth in cancer cells, but more recent drug discovery programs screen new molecules for inhibition of inflammation or activation of immune cells. Bexarotene is the first successful example of an effective therapeutic that molecularly targets RXR; this drug was approved to treat cutaneous T cell lymphoma and is still used as a standard of care treatment for this disease. No additional RXR agonists have yet achieved FDA approval, but several promising novel compounds are being developed. In this review, we provide an overview of the multiple mechanisms by which RXR signaling regulates inflammation and tumor immunity. We also discuss the potential of RXR-dependent immune cell modulation for the treatment or prevention of cancer and concomitant challenges and opportunities.
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Affiliation(s)
- Ana S Leal
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI, United States of America; Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, United States of America
| | - Pei-Yu Hung
- Department of Physiology, Michigan State University, East Lansing, MI, United States of America
| | - Afrin Sultana Chowdhury
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, IN, United States of America
| | - Karen T Liby
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI, United States of America; Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, United States of America.
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Sun C, Chen S. Disease-causing mutations in genes encoding transcription factors critical for photoreceptor development. Front Mol Neurosci 2023; 16:1134839. [PMID: 37181651 PMCID: PMC10172487 DOI: 10.3389/fnmol.2023.1134839] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Accepted: 04/04/2023] [Indexed: 05/16/2023] Open
Abstract
Photoreceptor development of the vertebrate visual system is controlled by a complex transcription regulatory network. OTX2 is expressed in the mitotic retinal progenitor cells (RPCs) and controls photoreceptor genesis. CRX that is activated by OTX2 is expressed in photoreceptor precursors after cell cycle exit. NEUROD1 is also present in photoreceptor precursors that are ready to specify into rod and cone photoreceptor subtypes. NRL is required for the rod fate and regulates downstream rod-specific genes including the orphan nuclear receptor NR2E3 which further activates rod-specific genes and simultaneously represses cone-specific genes. Cone subtype specification is also regulated by the interplay of several transcription factors such as THRB and RXRG. Mutations in these key transcription factors are responsible for ocular defects at birth such as microphthalmia and inherited photoreceptor diseases such as Leber congenital amaurosis (LCA), retinitis pigmentosa (RP) and allied dystrophies. In particular, many mutations are inherited in an autosomal dominant fashion, including the majority of missense mutations in CRX and NRL. In this review, we describe the spectrum of photoreceptor defects that are associated with mutations in the above-mentioned transcription factors, and summarize the current knowledge of molecular mechanisms underlying the pathogenic mutations. At last, we deliberate the outstanding gaps in our understanding of the genotype-phenotype correlations and outline avenues for future research of the treatment strategies.
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Affiliation(s)
- Chi Sun
- Department of Ophthalmology and Visual Sciences, Washington University in St. Louis, St. Louis, MO, United States
- *Correspondence: Chi Sun,
| | - Shiming Chen
- Department of Ophthalmology and Visual Sciences, Washington University in St. Louis, St. Louis, MO, United States
- Department of Developmental Biology, Washington University in St. Louis, St. Louis, MO, United States
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Design, synthesis and biological evaluation of acyl hydrazones-based derivatives as RXRα-targeted anti-mitotic agents. Bioorg Chem 2022; 128:106069. [DOI: 10.1016/j.bioorg.2022.106069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 07/11/2022] [Accepted: 07/28/2022] [Indexed: 11/20/2022]
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Weber SR, Zhao Y, Ma J, Gates C, da Veiga Leprevost F, Basrur V, Nesvizhskii AI, Gardner TW, Sundstrom JM. A validated analysis pipeline for mass spectrometry-based vitreous proteomics: new insights into proliferative diabetic retinopathy. Clin Proteomics 2021; 18:28. [PMID: 34861815 PMCID: PMC8903510 DOI: 10.1186/s12014-021-09328-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Accepted: 09/01/2021] [Indexed: 12/11/2022] Open
Abstract
Background Vitreous is an accessible, information-rich biofluid that has recently been studied as a source of retinal disease-related proteins and pathways. However, the number of samples required to confidently identify perturbed pathways remains unknown. In order to confidently identify these pathways, power analysis must be performed to determine the number of samples required, and sample preparation and analysis must be rigorously defined. Methods Control (n = 27) and proliferative diabetic retinopathy (n = 23) vitreous samples were treated as biologically distinct individuals or pooled together and aliquoted into technical replicates. Quantitative mass spectrometry with tandem mass tag labeling was used to identify proteins in individual or pooled control samples to determine technical and biological variability. To determine effect size and perform power analysis, control and proliferative diabetic retinopathy samples were analyzed across four 10-plexes. Pooled samples were used to normalize the data across plexes and generate a single data matrix for downstream analysis. Results The total number of unique proteins identified was 1152 in experiment 1, 989 of which were measured in all samples. In experiment 2, 1191 proteins were identified, 727 of which were measured across all samples in all plexes. Data are available via ProteomeXchange with identifier PXD025986. Spearman correlations of protein abundance estimations revealed minimal technical (0.99–1.00) and biological (0.94–0.98) variability. Each plex contained two unique pooled samples: one for normalizing across each 10-plex, and one to internally validate the normalization algorithm. Spearman correlation of the validation pool following normalization was 0.86–0.90. Principal component analysis revealed stratification of samples by disease and not by plex. Subsequent differential expression and pathway analyses demonstrated significant activation of metabolic pathways and inhibition of neuroprotective pathways in proliferative diabetic retinopathy samples relative to controls. Conclusions This study demonstrates a feasible, rigorous, and scalable method that can be applied to future proteomic studies of vitreous and identifies previously unrecognized metabolic pathways that advance understanding of diabetic retinopathy. Supplementary Information The online version contains supplementary material available at 10.1186/s12014-021-09328-8.
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Affiliation(s)
- Sarah R Weber
- Department of Ophthalmology, Penn State College of Medicine, 500 University Drive, Hershey, PA, 17033, USA.,Kellogg Eye Center, University of Michigan Medical School, 1000 Wall Street, Ann Arbor, MI, 48105, USA
| | - Yuanjun Zhao
- Department of Ophthalmology, Penn State College of Medicine, 500 University Drive, Hershey, PA, 17033, USA
| | - Jingqun Ma
- Department of Pathology, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN, 38105, USA
| | - Christopher Gates
- Bioinformatics Core, Biomedical Research Core Facilities, University of Michigan Medical School, 2800 Plymouth Road, Ann Arbor, MI, 48109, USA
| | - Felipe da Veiga Leprevost
- Department of Pathology, University of Michigan Medical School, 1301 Catherine Street, Ann Arbor, MI, 48109, USA
| | - Venkatesha Basrur
- Department of Pathology, University of Michigan Medical School, 1301 Catherine Street, Ann Arbor, MI, 48109, USA
| | - Alexey I Nesvizhskii
- Department of Pathology, University of Michigan Medical School, 1301 Catherine Street, Ann Arbor, MI, 48109, USA.,Department of Computational Medicine and Bioinformatics, University of Michigan, 100 Washtenaw Ave, Ann Arbor, MI, 48109, USA
| | - Thomas W Gardner
- Kellogg Eye Center, University of Michigan Medical School, 1000 Wall Street, Ann Arbor, MI, 48105, USA
| | - Jeffrey M Sundstrom
- Department of Ophthalmology, Penn State College of Medicine, 500 University Drive, Hershey, PA, 17033, USA. .,Kellogg Eye Center, University of Michigan Medical School, 1000 Wall Street, Ann Arbor, MI, 48105, USA.
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Yu H, Wang S, Hu W, Xu L, Ding Y, Kong D, Pan H. Association between Single-nucleotide Polymorphisms of RXRG and Genetic Susceptibility to Type 2 Diabetes in South China. Curr Mol Med 2021; 20:408-414. [PMID: 31808386 DOI: 10.2174/1566524020666191206163951] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Revised: 09/18/2019] [Accepted: 10/08/2019] [Indexed: 01/18/2023]
Abstract
OBJECTIVE To investigate the relationship between genetic polymorphisms of RXRG rs1467664, rs3753898 and the genetic susceptibility of type 2 diabetes in the Chinese Han population from South China. METHODS In our case-control study, single-nucleotide polymorphisms (SNPs) rs1467664 and rs3753898 were genotyped by SNPscanTM kit in 1092 patients with T2D as cases and 1092 normal persons as controls. The distributions of genotype and allele frequencies in two groups were analyzed by the SPSS 20.0 software. RESULTS The distribution of genotypes and alleles of RXRG rs3753898 was statistically significant between the two groups, but there was no significant difference in the distribution of genotypes and alleles of the rs1467664. Before and after the adjustment of age, sex and BMI, rs3753898 in the two groups had statistical significance under the additive, dominant and recessive models (P<0.05), but no statistical differences were found under the overdominance and co-dominant genetic models (P>0.05). There was no significant difference in the genetic models of rs1467664 between the two groups (P>0.05). The haplotype, which consists of rs1467664 allele T and rs3753898 allele A was a high-risk factor for T2D, OR=1.27, 95% CI (1.09-1.47), Padj=0.002. CONCLUSION Our results showed that the single nucleotide polymorphism of RXRG rs3753898 may be related to genetic susceptibility of type 2 diabetes. The haplotype consisting of the allele T of rs1467664 and the allele A of rs3753898 is a risk factor for type 2 diabetes, suggesting that the genetic variation of RXRG gene may be the genetic cause of diabetes mellitus in the Chinese Han population.
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Affiliation(s)
- Haibing Yu
- Department of Epidemiology and Medical Statistics, School of Public Health, Guangdong Medical University, Dongguan, China
| | - Shu Wang
- Department of Epidemiology and Medical Statistics, School of Public Health, Guangdong Medical University, Dongguan, China
| | - Wei Hu
- Department of Epidemiology and Medical Statistics, School of Public Health, Guangdong Medical University, Dongguan, China
| | - Lin Xu
- Department of Epidemiology and Medical Statistics, School of Public Health, Guangdong Medical University, Dongguan, China
| | - Yuanlin Ding
- Department of Epidemiology and Medical Statistics, School of Public Health, Guangdong Medical University, Dongguan, China
| | - Danli Kong
- Department of Epidemiology and Medical Statistics, School of Public Health, Guangdong Medical University, Dongguan, China
| | - Haiyan Pan
- Department of Epidemiology and Medical Statistics, School of Public Health, Guangdong Medical University, Dongguan, China
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Leal AS, Reich LA, Moerland JA, Zhang D, Liby KT. Potential therapeutic uses of rexinoids. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2021; 91:141-183. [PMID: 34099107 DOI: 10.1016/bs.apha.2021.01.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The discovery of nuclear receptors, particularly retinoid X receptors (RXR), and their involvement in numerous pathways related to development sparked interest in their immunomodulatory properties. Genetic models using deletion or overexpression of RXR and the subsequent development of several small molecules that are agonists or antagonists of this receptor support a promising therapeutic role for these receptors in immunology. Bexarotene was approved in 1999 for the treatment of cutaneous T cell lymphoma. Several other small molecule RXR agonists have since been synthesized with limited preclinical development, but none have yet achieved FDA approval. Cancer treatment has recently been revolutionized with the introduction of immune checkpoint inhibitors, but their success has been restricted to a minority of patients. This review showcases the emerging immunomodulatory effects of RXR and the potential of small molecules that target this receptor as therapies for cancer and other diseases. Here we describe the essential roles that RXR and partner receptors play in T cells, dendritic cells, macrophages and epithelial cells, especially within the tumor microenvironment. Most of these effects are site and cancer type dependent but skew immune cells toward an anti-inflammatory and anti-tumor effect. This beneficial effect on immune cells supports the promise of combining rexinoids with approved checkpoint blockade therapies in order to enhance efficacy of the latter and to delay or potentially eliminate drug resistance. The data compiled in this review strongly suggest that targeting RXR nuclear receptors is a promising new avenue in immunomodulation for cancer and other chronic inflammatory diseases.
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Affiliation(s)
- Ana S Leal
- Department of Pharmacology & Toxicology, Michigan State University, East Lansing, MI, United States
| | - Lyndsey A Reich
- Department of Pharmacology & Toxicology, Michigan State University, East Lansing, MI, United States
| | - Jessica A Moerland
- Department of Pharmacology & Toxicology, Michigan State University, East Lansing, MI, United States
| | - Di Zhang
- Department of Pharmacology & Toxicology, Michigan State University, East Lansing, MI, United States
| | - Karen T Liby
- Department of Pharmacology & Toxicology, Michigan State University, East Lansing, MI, United States.
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Gallardo-Escribano C, Buonaiuto V, Ruiz-Moreno MI, Vargas-Candela A, Vilches-Perez A, Benitez-Porres J, Romance-Garcia AR, Ruiz-Moreno A, Gomez-Huelgas R, Bernal-Lopez MR. Epigenetic approach in obesity: DNA methylation in a prepubertal population which underwent a lifestyle modification. Clin Epigenetics 2020; 12:144. [PMID: 32967728 PMCID: PMC7509923 DOI: 10.1186/s13148-020-00935-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Accepted: 09/03/2020] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Metabolically healthy obesity (MHO) is a considerably controversial concept as it is considered a transitory condition towards the development of different pathologies (type 2 diabetes, insulin resistance, or cardiovascular disease). MHO is closely related to lifestyle and environmental factors. Epigenetics has become an essential biological tool to analyze the link between obesity and metabolic status. The aim of this study was to determine whether MHO status is conditioned by the DNA methylation (DNAm) of several genes related to lipid metabolism (lipoprotein lipase, retinoid X receptor alpha, liver X receptor, stearoyl-CoA desaturase, sterol regulatory element binding factor 1), and inflammation (LEP) in peripheral blood mononuclear cells (PBMCs) from 131 prepubertal subjects with MHO phenotype after lifestyle modifications with personalized Mediterranean diet (MedDiet) combined with a physical activity (PA) program. RESULTS The DNAm of all studied genes were significantly modified in the population after 12 months of lifestyle modifications (MedDiet and PA). In addition, associations were found between the DNAm studies and BMI, homeostatic model assessment of insulin resistance, monounsaturated fatty acid and polyunsaturated fatty acid, moderate-vigorous PA, fat mass, and adherence to MedDiet. CONCLUSIONS It was found that DNAm of genes related to lipid metabolism and inflammation are also present in childhood and that this methylation profile can be modified by interventions based on MedDiet and PA.
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Affiliation(s)
| | - Verónica Buonaiuto
- Internal Medicine Department, Instituto de Investigación Biomédica de Malaga (IBIMA), Regional University Hospital of Malaga, Malaga, Spain
| | - M Isabel Ruiz-Moreno
- Internal Medicine Department, Instituto de Investigación Biomédica de Malaga (IBIMA), Regional University Hospital of Malaga, Malaga, Spain
| | - Antonio Vargas-Candela
- Internal Medicine Department, Instituto de Investigación Biomédica de Malaga (IBIMA), Regional University Hospital of Malaga, Malaga, Spain
| | - Alberto Vilches-Perez
- Endocrinology and Nutrition Department, Instituto de Investigación Biomédica de Malaga (IBIMA), University Hospital Virgen de la Victoria, Malaga, Spain
| | - Javier Benitez-Porres
- Department of Human Physiology, Physical Education and Sports. Faculty of Medicine, University of Malaga, Malaga, Spain
| | - Angel Ramon Romance-Garcia
- Biodynamic and Body Composition Laboratory. Department of Didactics of Language, Arts, and Sport. Faculty of Education Science, University of Málaga, Malaga, Spain
| | - Alejandro Ruiz-Moreno
- Internal Medicine Department, Instituto de Investigación Biomédica de Malaga (IBIMA), Regional University Hospital of Malaga, Malaga, Spain
| | - Ricardo Gomez-Huelgas
- Internal Medicine Department, Instituto de Investigación Biomédica de Malaga (IBIMA), Regional University Hospital of Malaga, Malaga, Spain.
- CIBER Patofisiología de la Obesidad y la Nutrición, Carlos III Health Institute, Madrid, Spain.
| | - M Rosa Bernal-Lopez
- Internal Medicine Department, Instituto de Investigación Biomédica de Malaga (IBIMA), Regional University Hospital of Malaga, Malaga, Spain.
- CIBER Patofisiología de la Obesidad y la Nutrición, Carlos III Health Institute, Madrid, Spain.
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Li K, Wang F, Yang ZN, Cui B, Li PP, Li ZY, Hu ZW, Zhu HH. PML-RARα interaction with TRIB3 impedes PPARγ/RXR function and triggers dyslipidemia in acute promyelocytic leukemia. Am J Cancer Res 2020; 10:10326-10340. [PMID: 32929351 PMCID: PMC7481410 DOI: 10.7150/thno.45924] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Accepted: 07/16/2020] [Indexed: 12/18/2022] Open
Abstract
Although dyslipidemia commonly occurs in patients with acute promyelocytic leukemia (APL) in response to anti-APL therapy, the underlying mechanism and the lipid statuses of patients with newly diagnosed APL remain to be addressed. Methods: We conducted a retrospective study to investigate the lipid profiles of APL patients. PML-RARα transgenic mice and APL cells-transplanted mice were used to assess the effects of APL cells on the blood/liver lipid levels. Subsequently, gene set enrichment analysis, western blot and dual luciferase reporter assay were performed to examine the role and mechanism of PML-RARα and TRIB3 in lipid metabolism regulation in APL patients at pretreatment and after induction therapy. Results: APL patients exhibited a higher prevalence of dyslipidemia before anti-APL therapy based on a retrospective study. Furthermore, APL cells caused secretion of triglycerides, cholesterol, and PCSK9 from hepatocytes and degradation of low-density lipoprotein receptors in hepatocytes, which elevated the lipid levels in APL cell-transplanted mice and Pml-Rarα transgenic mice. Mechanistically, pseudokinase TRIB3 interacted with PML-RARα to inhibit PPARγ activity by interfering with the interaction of PPARγ and RXR and promoting PPARγ degradation. Thus, reduced PPARγ activity in APL cells decreased leptin but increased resistin expression, causing lipid metabolism disorder in hepatocytes and subsequent dyslipidemia in mice. Although arsenic/ATRA therapy degraded PML-RARα and restored PPARγ expression, it exacerbated dyslipidemia in APL patients. The elevated TRIB3 expression in response to arsenic/ATRA therapy suppressed PPARγ activity by disrupting the PPARγ/RXR dimer, which resulted in dyslipidemia in APL patients undergoing therapy. Indeed, the PPAR activator not only enhanced the anti-APL effects of arsenic/ATRA by suppressing TRIB3 expression but also reduced therapy-induced dyslipidemia in APL patients. Conclusion: Our work reveals the critical role of the PML-RARα/PPARγ/TRIB3 axis in the development of dyslipidemia in APL patients, potentially conferring a rationale for combining ATRA/arsenic with the PPAR activator for APL treatment.
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Yang J, Li X, Xu D. Research Progress on the Involvement of ANGPTL4 and Loss-of-Function Variants in Lipid Metabolism and Coronary Heart Disease: Is the "Prime Time" of ANGPTL4-Targeted Therapy for Coronary Heart Disease Approaching? Cardiovasc Drugs Ther 2020; 35:467-477. [PMID: 32500296 DOI: 10.1007/s10557-020-07001-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
BACKGROUND Multiple genetic studies have confirmed the definitive link among the loss-of-function variants of angiogenin-like protein 4 (ANGPTL4), significantly decreased plasma triglyceride (TG) levels, and reduced risk of coronary heart disease (CHD). The potential therapeutic effect of ANGPTL4 on dyslipidemia and CHD has been widely studied. OBJECTIVE This review provides a detailed introduction to the research progress on the involvement of ANGPTL4 in lipid metabolism and atherosclerosis and evaluates the efficacy and safety of ANGPTL4 as a therapeutic target for CHD. RELEVANT FINDINGS By inhibiting lipoprotein lipase (LPL) activity, ANGPTL4 plays a vital role in the regulation of lipid metabolism and energy balance. However, the role of ANGPTL4 in regulating lipid metabolism is tissue-specific. ANGPTL4 acts as a locally released LPL inhibitor in the heart, skeletal muscle and small intestine, while ANGPTL4 derived from liver and adipose tissue mainly acts as an endocrine factor that regulates systemic lipid metabolism. As a multifunctional protein, ANGPTL4 also inhibits the formation of foam cells in macrophages, exerting an anti-atherogenic role. The function of ANGPTL4 in endothelial cells is still uncertain. The safety of ANGPTL4 monoclonal antibodies requires further evaluation due to their potential adverse effects. CONCLUSION The biological characteristics of ANGPTL4 are much more complex than those demonstrated by genetic studies. Future studies must elucidate how to effectively reduce the risk of CHD while avoiding potential atherogenic effects and other complications before the "prime time" of ANGPTL4-targeted therapy arrives.
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Affiliation(s)
- Jingmin Yang
- Department of Cardiology, The Second Xiangya Hospital, Central South University, 139 Middle Renmin Road, Changsha, 410000, Hunan, China
| | - Xiao Li
- Department of Cardiology, The Second Xiangya Hospital, Central South University, 139 Middle Renmin Road, Changsha, 410000, Hunan, China
| | - Danyan Xu
- Department of Cardiology, The Second Xiangya Hospital, Central South University, 139 Middle Renmin Road, Changsha, 410000, Hunan, China.
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Raja Gopal Reddy M, Pavan Kumar C, Mahesh M, Sravan Kumar M, Mullapudi Venkata S, Putcha UK, Vajreswari A, Jeyakumar SM. Vitamin A deficiency suppresses high fructose-induced triglyceride synthesis and elevates resolvin D1 levels. Biochim Biophys Acta Mol Cell Biol Lipids 2015; 1861:156-65. [PMID: 26597784 DOI: 10.1016/j.bbalip.2015.11.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Revised: 11/04/2015] [Accepted: 11/14/2015] [Indexed: 02/08/2023]
Abstract
BACKGROUND/AIMS Vitamin A and its metabolites are known to regulate lipid metabolism. However so far, no study has assessed, whether vitamin A deficiency per se aggravates or attenuates the development of non-alcoholic fatty liver disease (NAFLD). Therefore, here, we tested the impact of vitamin A deficiency on the development of NAFLD. METHODS Male weanling Wistar rats were fed one of the following diets; control, vitamin A-deficient (VAD), high fructose (HFr) and VAD with HFr (VADHFr) of AIN93G composition, for 16weeks, except half of the VAD diet-fed rats were shifted to HFr diet (VAD(s)HFr), at the end of 8(th) week. RESULTS Animals fed on VAD diet with HFr displayed hypotriglyceridemia (33.5mg/dL) with attenuated hepatic triglyceride accumulation (8.2mg/g), compared with HFr diet (89.5mg/dL and 20.6mg/g respectively). These changes could be partly explained by the decreased activity of glycerol 3-phosphate dehydrogenase (GPDH) and the down-regulation of stearoyl CoA desaturase 1 (SCD1), both at gene and protein levels, the key determinants of triglyceride biosynthesis. On the other hand, n-3 long chain polyunsaturated fatty acid, docosahexaenoic acid and its active metabolite; resolvin D1 (RvD1) levels were elevated in the liver and plasma of VAD diet-fed groups, which was negatively associated with triglyceride levels. All these factors confer vitamin A deficiency-mediated protection against the development of hepatic steatosis, which was also evident from the group shifted from VAD to HFr diet. CONCLUSIONS Vitamin A deficiency attenuates high fructose-induced hepatic steatosis, by regulating triglyceride synthesis, possibly through GPDH, SCD1 and RvD1.
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Affiliation(s)
- Mooli Raja Gopal Reddy
- Lipid Biochemistry Division, National Institute of Nutrition, Jamai Osmania, Hyderabad 500007, India
| | - Chodisetti Pavan Kumar
- Lipid Biochemistry Division, National Institute of Nutrition, Jamai Osmania, Hyderabad 500007, India
| | - Malleswarapu Mahesh
- Lipid Biochemistry Division, National Institute of Nutrition, Jamai Osmania, Hyderabad 500007, India
| | - Manchiryala Sravan Kumar
- Lipid Biochemistry Division, National Institute of Nutrition, Jamai Osmania, Hyderabad 500007, India
| | | | - Uday Kumar Putcha
- Pathology Division, National Institute of Nutrition, Jamai Osmania, Hyderabad 500007, India
| | | | - Shanmugam M Jeyakumar
- Lipid Biochemistry Division, National Institute of Nutrition, Jamai Osmania, Hyderabad 500007, India.
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The Rexinoids LG100268 and LG101506 Inhibit Inflammation and Suppress Lung Carcinogenesis in A/J Mice. Cancer Prev Res (Phila) 2015; 9:105-14. [DOI: 10.1158/1940-6207.capr-15-0325] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Accepted: 11/03/2015] [Indexed: 11/16/2022]
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Wang Y, Li WH, Li Z, Liu W, Zhou L, Gui JF. BMP and RA signaling cooperate to regulate Apolipoprotein C1 expression during embryonic development. Gene 2015; 554:196-204. [DOI: 10.1016/j.gene.2014.10.047] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2014] [Revised: 10/14/2014] [Accepted: 10/27/2014] [Indexed: 12/20/2022]
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Kawata K, Morishita KI, Nakayama M, Yamada S, Kobayashi T, Furusawa Y, Arimoto-Kobayashi S, Oohashi T, Makishima M, Naitou H, Ishitsubo E, Tokiwa H, Tai A, Kakuta H. RXR partial agonist produced by side chain repositioning of alkoxy RXR full agonist retains antitype 2 diabetes activity without the adverse effects. J Med Chem 2014; 58:912-26. [PMID: 25486327 DOI: 10.1021/jm501863r] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We previously reported RXR partial agonist CBt-PMN (1-(3,5,5,8,8-pentamethyl-5,6,7,8-tetrahydro-2-naphthyl)-1H-benzotriazole-5-carboxylic acid: 5, EC50 = 143 nM, Emax = 75%), which showed a potent glucose-lowering effect without causing serious adverse effects. However, it remains important to elucidate the structural requirements for RXR efficacy and the glucose-lowering effect because RXR-permissive heterodimers such as PPAR/RXR or LXR/RXR are reported to be activated differently depending upon the chemical structure of RXR agonists. In this work, we show that an RXR partial agonist, NEt-4IB (6-[ethyl-(4-isobutoxy-3-isopropylphenyl)amino]pyridine-3-carboxylic acid: 8b, EC50 = 169 nM, Emax = 55%), can be obtained simply by repositioning the side chains (interchanging the isobutoxy and isopropoxy groups) at the hydrophobic moiety of the RXR full agonist NEt-3IB (6-[ethyl-(3-isobutoxy-4-isopropylphenyl)amino]pyridine-3-carboxylic acid: 7b, EC50 = 19 nM). NEt-4IB (8b) showed antitype 2 diabetes activity without the above side effects upon repeated oral administration to mice at 10 mg/kg/day, similarly to 5.
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Affiliation(s)
- Kohei Kawata
- Division of Pharmaceutical Sciences, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences , 1-1-1, Tsushima-naka, Kita-ku Okayama 700-8530, Japan
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14
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Colombo R, Gallipoli P, Castelli R. Thrombosis and hemostatic abnormalities in hematological malignancies. CLINICAL LYMPHOMA MYELOMA & LEUKEMIA 2014; 14:441-50. [PMID: 25018062 DOI: 10.1016/j.clml.2014.05.003] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Accepted: 05/19/2014] [Indexed: 01/19/2023]
Abstract
There is a paucity of data that pertain to thrombosis in patients with hematological malignancies. Recent studies showed that patients with lymphoma, multiple myeloma, and acute leukemia have an increased thrombotic risk, particularly at the time of diagnosis and during chemotherapy. We searched the PubMed database for articles on thromboembolic complications in patients with hematological malignancies published between 1996 and 2013. The incidence of thrombotic events is variable, and is influenced by the type and the stage of hematological malignancy, the antitumor therapy, and the use of central venous devices. The pathogenesis of thromboembolic disease in hematological malignancies is multifactorial. Tumor cell-derived procoagulant, fibrinolytic, or proteolytic factors, and inflammatory cytokines affect clotting activation, and chemotherapy and immunomodulatory drugs increase the thrombotic risk in patients with lymphoma, acute leukemia, and multiple myeloma. Infections might also contribute to the pathogenesis of the thromboembolic complications: endotoxins from gram-negative bacteria induce the release of tissue factor, tumor necrosis factor and interleukin-1b, and gram-positive organisms can release bacterial mucopolysaccharides that directly activate factor XII. In the setting of plasma cell dyscrasias, hyperviscosity, decreased fibrinolysis, procoagulant autoantibody production, inflammatory cytokines, acquired activated protein C resistance, and the prothrombotic effects of antimyeloma agents might be the cause of thromboembolic complications. Anticoagulant therapy is very complicated because of high risk of hemorrhage. Therefore, an accurate estimate of a patient's thrombotic risk is essential to allow physicians to target thromboprophylaxis in high-risk patients.
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Affiliation(s)
- Riccardo Colombo
- Department of Pathophysiology and Transplantation, Internal Medicine Section, University of Milan, and Department of Haematology, Fondazione IRCCS Ca' Granda-Ospedale Maggiore Policlinico, Milan, Italy
| | - Paolo Gallipoli
- Department of Haematology, Addenbrooke's Hospital, Cambridge University Hospitals NHS Trust, Cambridge, UK
| | - Roberto Castelli
- Department of Pathophysiology and Transplantation, Internal Medicine Section, University of Milan, and Department of Haematology, Fondazione IRCCS Ca' Granda-Ospedale Maggiore Policlinico, Milan, Italy.
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15
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Kersten S. Physiological regulation of lipoprotein lipase. Biochim Biophys Acta Mol Cell Biol Lipids 2014; 1841:919-33. [PMID: 24721265 DOI: 10.1016/j.bbalip.2014.03.013] [Citation(s) in RCA: 335] [Impact Index Per Article: 33.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Revised: 03/27/2014] [Accepted: 03/30/2014] [Indexed: 01/01/2023]
Abstract
The enzyme lipoprotein lipase (LPL), originally identified as the clearing factor lipase, hydrolyzes triglycerides present in the triglyceride-rich lipoproteins VLDL and chylomicrons. LPL is primarily expressed in tissues that oxidize or store fatty acids in large quantities such as the heart, skeletal muscle, brown adipose tissue and white adipose tissue. Upon production by the underlying parenchymal cells, LPL is transported and attached to the capillary endothelium by the protein GPIHBP1. Because LPL is rate limiting for plasma triglyceride clearance and tissue uptake of fatty acids, the activity of LPL is carefully controlled to adjust fatty acid uptake to the requirements of the underlying tissue via multiple mechanisms at the transcriptional and post-translational level. Although various stimuli influence LPL gene transcription, it is now evident that most of the physiological variation in LPL activity, such as during fasting and exercise, appears to be driven via post-translational mechanisms by extracellular proteins. These proteins can be divided into two main groups: the liver-derived apolipoproteins APOC1, APOC2, APOC3, APOA5, and APOE, and the angiopoietin-like proteins ANGPTL3, ANGPTL4 and ANGPTL8, which have a broader expression profile. This review will summarize the available literature on the regulation of LPL activity in various tissues, with an emphasis on the response to diverse physiological stimuli.
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Affiliation(s)
- Sander Kersten
- Nutrition, Metabolism and Genomics Group, Division of Human Nutrition, Wageningen University, Bomenweg 2, 6703HD Wageningen, The Netherlands
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16
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Dijk W, Kersten S. Regulation of lipoprotein lipase by Angptl4. Trends Endocrinol Metab 2014; 25:146-55. [PMID: 24397894 DOI: 10.1016/j.tem.2013.12.005] [Citation(s) in RCA: 139] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2013] [Revised: 11/30/2013] [Accepted: 12/02/2013] [Indexed: 02/07/2023]
Abstract
Triglyceride (TG)-rich chylomicrons and very low density lipoproteins (VLDL) distribute fatty acids (FA) to various tissues by interacting with the enzyme lipoprotein lipase (LPL). The protein angiopoietin-like 4 (Angptl4) is under sensitive transcriptional control by FA and the FA-activated peroxisome proliferator activated receptors (PPARs), and its tissue expression largely overlaps with that of LPL. Growing evidence indicates that Angptl4 mediates the physiological fluctuations in LPL activity, including the decrease in adipose tissue LPL activity during fasting. This review focuses on the major ambiguities concerning the mechanism of LPL inhibition by Angptl4, as well as on the physiological role of Angptl4 in lipid metabolism, highlighting its function in a variety of tissues, and uses this information to make suggestions for further research.
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Affiliation(s)
- Wieneke Dijk
- Nutrition, Metabolism, and Genomics group, Wageningen University, Bomenweg 2, 6703 HD Wageningen, The Netherlands
| | - Sander Kersten
- Nutrition, Metabolism, and Genomics group, Wageningen University, Bomenweg 2, 6703 HD Wageningen, The Netherlands.
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17
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Chen G. Roles of Vitamin A Metabolism in the Development of Hepatic Insulin Resistance. ISRN HEPATOLOGY 2013; 2013:534972. [PMID: 27335827 PMCID: PMC4890907 DOI: 10.1155/2013/534972] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/02/2013] [Accepted: 08/18/2013] [Indexed: 02/07/2023]
Abstract
The increase in the number of people with obesity- and noninsulin-dependent diabetes mellitus has become a major public health concern. Insulin resistance is a common feature closely associated with human obesity and diabetes. Insulin regulates metabolism, at least in part, via the control of the expression of the hepatic genes involved in glucose and fatty acid metabolism. Insulin resistance is always associated with profound changes of the expression of hepatic genes for glucose and lipid metabolism. As an essential micronutrient, vitamin A (VA) is needed in a variety of physiological functions. The active metablite of VA, retinoic acid (RA), regulates the expression of genes through the activation of transcription factors bound to the RA-responsive elements in the promoters of RA-targeted genes. Recently, retinoids have been proposed to play roles in glucose and lipid metabolism and energy homeostasis. This paper summarizes the recent progresses in our understanding of VA metabolism in the liver and of the potential transcription factors mediating RA responses. These transcription factors are the retinoic acid receptor, the retinoid X receptor, the hepatocyte nuclear factor 4α, the chicken ovalbumin upstream promoter-transcription factor II, and the peroxisome proliferator-activated receptor β/δ. This paper also summarizes the effects of VA status and RA treatments on the glucose and lipid metabolism in vivo and the effects of retinoid treatments on the expression of insulin-regulated genes involved in the glucose and fatty acid metabolism in the primary hepatocytes. I discuss the roles of RA production in the development of insulin resistance in hepatocytes and proposes a mechanism by which RA production may contribute to hepatic insulin resistance. Given the large amount of information and progresses regarding the physiological functions of VA, this paper mainly focuses on the findings in the liver and hepatocytes and only mentions the relative findings in other tissues and cells.
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Affiliation(s)
- Guoxun Chen
- Department of Nutrition, University of Tennessee at Knoxville, Knoxville, TN 37996, USA
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18
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Ohsawa F, Yamada S, Yakushiji N, Shinozaki R, Nakayama M, Kawata K, Hagaya M, Kobayashi T, Kohara K, Furusawa Y, Fujiwara C, Ohta Y, Makishima M, Naitou H, Tai A, Yoshikawa Y, Yasui H, Kakuta H. Mechanism of Retinoid X Receptor Partial Agonistic Action of 1-(3,5,5,8,8-Pentamethyl-5,6,7,8-tetrahydro-2-naphthyl)-1H-benzotriazole-5-carboxylic Acid and Structural Development To Increase Potency. J Med Chem 2013; 56:1865-77. [DOI: 10.1021/jm400033f] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Fuminori Ohsawa
- Division of
Pharmaceutical Sciences, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 1-1-1, Tsushima-Naka, Kita-Ku, Okayama 700-8530,
Japan
| | - Shoya Yamada
- Division of
Pharmaceutical Sciences, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 1-1-1, Tsushima-Naka, Kita-Ku, Okayama 700-8530,
Japan
- Research Fellowship
Division, Japan Society for the Promotion of Science, Sumitomo-Ichibancho
FS Bldg., 8 Ichibancho, Chiyoda-ku, Tokyo 102-8472, Japan
| | - Nobumasa Yakushiji
- Division of
Pharmaceutical Sciences, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 1-1-1, Tsushima-Naka, Kita-Ku, Okayama 700-8530,
Japan
| | - Ryosuke Shinozaki
- Division of
Pharmaceutical Sciences, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 1-1-1, Tsushima-Naka, Kita-Ku, Okayama 700-8530,
Japan
| | - Mariko Nakayama
- Division of
Pharmaceutical Sciences, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 1-1-1, Tsushima-Naka, Kita-Ku, Okayama 700-8530,
Japan
| | - Kohei Kawata
- Division of
Pharmaceutical Sciences, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 1-1-1, Tsushima-Naka, Kita-Ku, Okayama 700-8530,
Japan
| | - Manabu Hagaya
- Division of
Pharmaceutical Sciences, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 1-1-1, Tsushima-Naka, Kita-Ku, Okayama 700-8530,
Japan
| | - Toshiki Kobayashi
- Division of
Pharmaceutical Sciences, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 1-1-1, Tsushima-Naka, Kita-Ku, Okayama 700-8530,
Japan
| | - Kazutaka Kohara
- Division of
Pharmaceutical Sciences, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 1-1-1, Tsushima-Naka, Kita-Ku, Okayama 700-8530,
Japan
| | - Yuuki Furusawa
- Division of
Pharmaceutical Sciences, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 1-1-1, Tsushima-Naka, Kita-Ku, Okayama 700-8530,
Japan
| | - Chisa Fujiwara
- Division of
Pharmaceutical Sciences, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 1-1-1, Tsushima-Naka, Kita-Ku, Okayama 700-8530,
Japan
| | - Yui Ohta
- Division of
Pharmaceutical Sciences, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 1-1-1, Tsushima-Naka, Kita-Ku, Okayama 700-8530,
Japan
| | - Makoto Makishima
- Division of Biochemistry, Department
of Biomedical Sciences, Nihon University School of Medicine, 30-1 Oyaguchi-kamicho, Itabashi-ku, Tokyo 173-8610, Japan
| | - Hirotaka Naitou
- Graduate School of Nutritional
and Environmental Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Japan
| | - Akihiro Tai
- Faculty of Life and Environmental
Sciences, Prefectural University of Hiroshima, 562 Nanatsuka-Cho, Shobara, Hiroshima 727-0023, Japan
| | - Yutaka Yoshikawa
- Department of Analytical and Bioinorganic Chemistry, Division of Analytical and Physical Chemistry, Kyoto Pharmaceutical University, 5 Nakauchi-cho, Misasagi, Yamashina-ku, Kyoto 607-8414, Japan
| | - Hiroyuki Yasui
- Department of Analytical and Bioinorganic Chemistry, Division of Analytical and Physical Chemistry, Kyoto Pharmaceutical University, 5 Nakauchi-cho, Misasagi, Yamashina-ku, Kyoto 607-8414, Japan
| | - Hiroki Kakuta
- Division of
Pharmaceutical Sciences, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 1-1-1, Tsushima-Naka, Kita-Ku, Okayama 700-8530,
Japan
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19
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Robciuc MR, Skrobuk P, Anisimov A, Olkkonen VM, Alitalo K, Eckel RH, Koistinen HA, Jauhiainen M, Ehnholm C. Angiopoietin-like 4 mediates PPAR delta effect on lipoprotein lipase-dependent fatty acid uptake but not on beta-oxidation in myotubes. PLoS One 2012; 7:e46212. [PMID: 23056264 PMCID: PMC3464237 DOI: 10.1371/journal.pone.0046212] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2012] [Accepted: 08/30/2012] [Indexed: 12/12/2022] Open
Abstract
Peroxisome proliferator-activated receptor (PPAR) delta is an important regulator of fatty acid (FA) metabolism. Angiopoietin-like 4 (Angptl4), a multifunctional protein, is one of the major targets of PPAR delta in skeletal muscle cells. Here we investigated the regulation of Angptl4 and its role in mediating PPAR delta functions using human, rat and mouse myotubes. Expression of Angptl4 was upregulated during myotubes differentiation and by oleic acid, insulin and PPAR delta agonist GW501516. Treatment with GW501516 or Angptl4 overexpression inhibited both lipoprotein lipase (LPL) activity and LPL-dependent uptake of FAs whereas uptake of BSA-bound FAs was not affected by either treatment. Activation of retinoic X receptor (RXR), PPAR delta functional partner, using bexarotene upregulated Angptl4 expression and inhibited LPL activity in a PPAR delta dependent fashion. Silencing of Angptl4 blocked the effect of GW501516 and bexarotene on LPL activity. Treatment with GW501516 but not Angptl4 overexpression significantly increased palmitate oxidation. Furthermore, Angptl4 overexpression did not affect the capacity of GW501516 to increase palmitate oxidation. Basal and insulin stimulated glucose uptake, glycogen synthesis and glucose oxidation were not significantly modulated by Angptl4 overexpression. Our findings suggest that FAs-PPARdelta/RXR-Angptl4 axis controls the LPL-dependent uptake of FAs in myotubes, whereas the effect of PPAR delta activation on beta-oxidation is independent of Angptl4.
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Affiliation(s)
- Marius R Robciuc
- Department of Chronic Disease Prevention, National Institute for Health and Welfare, Helsinki, Finland.
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20
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Berglund L, Brunzell JD, Goldberg AC, Goldberg IJ, Sacks F, Murad MH, Stalenhoef AFH. Evaluation and treatment of hypertriglyceridemia: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab 2012; 97:2969-89. [PMID: 22962670 PMCID: PMC3431581 DOI: 10.1210/jc.2011-3213] [Citation(s) in RCA: 531] [Impact Index Per Article: 44.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
OBJECTIVE The aim was to develop clinical practice guidelines on hypertriglyceridemia. PARTICIPANTS The Task Force included a chair selected by The Endocrine Society Clinical Guidelines Subcommittee (CGS), five additional experts in the field, and a methodologist. The authors received no corporate funding or remuneration. CONSENSUS PROCESS Consensus was guided by systematic reviews of evidence, e-mail discussion, conference calls, and one in-person meeting. The guidelines were reviewed and approved sequentially by The Endocrine Society's CGS and Clinical Affairs Core Committee, members responding to a web posting, and The Endocrine Society Council. At each stage, the Task Force incorporated changes in response to written comments. CONCLUSIONS The Task Force recommends that the diagnosis of hypertriglyceridemia be based on fasting levels, that mild and moderate hypertriglyceridemia (triglycerides of 150-999 mg/dl) be diagnosed to aid in the evaluation of cardiovascular risk, and that severe and very severe hypertriglyceridemia (triglycerides of > 1000 mg/dl) be considered a risk for pancreatitis. The Task Force also recommends that patients with hypertriglyceridemia be evaluated for secondary causes of hyperlipidemia and that subjects with primary hypertriglyceridemia be evaluated for family history of dyslipidemia and cardiovascular disease. The Task Force recommends that the treatment goal in patients with moderate hypertriglyceridemia be a non-high-density lipoprotein cholesterol level in agreement with National Cholesterol Education Program Adult Treatment Panel guidelines. The initial treatment should be lifestyle therapy; a combination of diet modification and drug therapy may also be considered. In patients with severe or very severe hypertriglyceridemia, a fibrate should be used as a first-line agent.
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Affiliation(s)
- Lars Berglund
- University of California, Davis, Sacramento, California 95817, USA
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21
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Kiefer FW, Orasanu G, Nallamshetty S, Brown JD, Wang H, Luger P, Qi NR, Burant CF, Duester G, Plutzky J. Retinaldehyde dehydrogenase 1 coordinates hepatic gluconeogenesis and lipid metabolism. Endocrinology 2012; 153:3089-99. [PMID: 22555438 PMCID: PMC3380298 DOI: 10.1210/en.2011-2104] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Recent data link vitamin A and its retinoid metabolites to the regulation of adipogenesis, insulin sensitivity, and glucose homeostasis. Retinoid metabolism is tightly controlled by an enzymatic network in which retinaldehyde dehydrogenases (Aldh1-3) are the rate-limiting enzymes that convert retinaldehyde to retinoic acid. Aldh1a1-deficient mice are protected from diet-induced obesity and hence diabetes. Here we investigated whether Aldh1a1 and the retinoid axis regulate hepatic glucose and lipid metabolism independent of adiposity. The impact of Aldh1a1 and the retinoid pathway on glucose homeostasis and lipid metabolism was analyzed in hepatocytes in vitro and in chow-fed, weight-matched Aldh1a1-deficient vs. wild-type (WT) mice in vivo. Aldh1a1-deficient mice displayed significantly decreased fasting glucose concentrations compared with WT controls as a result of attenuated hepatic glucose production. Expression of key gluconeogenic enzymes as well as the activity of Forkhead box O1 was decreased in Aldh1a1-deficient vs. WT livers. In vitro, retinoid or cAMP agonist stimulation markedly induced gluconeogenesis in WT but not Aldh1a1-deficient primary hepatocytes. Aldh1a1 deficiency increased AMP-activated protein kinase α activity, decreased expression of lipogenic targets of AMP-activated protein kinase α and significantly attenuated hepatic triacylglycerol synthesis. In metabolic cage studies, lean Aldh1a1-deficient mice manifested enhanced oxygen consumption and reduced respiratory quotient vs. WT controls, consistent with increased expression of fatty acid oxidation markers in skeletal muscle. Taken together, this work establishes a role for retinoid metabolism in glucose homeostasis in vivo and for Aldh1a1 as a novel determinant of gluconeogenesis and lipid metabolism independent of adiposity.
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Affiliation(s)
- Florian W Kiefer
- Cardiovascular Division, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, Massachusetts 02115, USA
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22
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Abstract
Retinoid acid is a metabolite of vitamin A and functions as an important factor in cell survival, differentiation and death. Most previous studies on retinoid metabolism have focused on its association with cancer, hematologic and dermatologic disorders. Given the special concern over the recent increase in the prevalence of diabetes worldwide, the role of retinoid metabolism on glucose metabolism and insulin resistance in the human body is of marked importance. Therefore, in this issue, we review the literature on the association of retinoid metabolism with glucose tolerance, with regard to insulin secretion, pancreatic autoimmunity, insulin sensitivity and lipid metabolism. Further, we tried to assess the possibility of using retinoids as a novel therapeutic strategy for diabetes.
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Affiliation(s)
- Eun-Jung Rhee
- Department of Endocrinology and Metabolism, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Jorge Plutzky
- Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
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23
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Kakuta H, Yakushiji N, Shinozaki R, Ohsawa F, Yamada S, Ohta Y, Kawata K, Nakayama M, Hagaya M, Fujiwara C, Makishima M, Uno S, Tai A, Maehara A, Nakayama M, Oohashi T, Yasui H, Yoshikawa Y. RXR Partial Agonist CBt-PMN Exerts Therapeutic Effects on Type 2 Diabetes without the Side Effects of RXR Full Agonists. ACS Med Chem Lett 2012; 3:427-32. [PMID: 24900488 DOI: 10.1021/ml300055n] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2012] [Accepted: 04/08/2012] [Indexed: 01/26/2023] Open
Abstract
Treating insulin resistance and type 2 diabetes in rodents, currently known retinoid X receptor (RXR) agonists induce significant adverse effects. Here we introduce a novel RXR partial agonist CBt-PMN (11b), which shows a potent glucose-lowering effect and improvements of insulin secretion and glucose tolerance without the serious adverse effects caused by RXR full agonists. We suggest that RXR partial agonists may be a new class of antitype 2 diabetes drug candidates.
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Affiliation(s)
- Hiroki Kakuta
- Division of Pharmaceutical Sciences, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 1-1-1 Tsushima-Naka, Okayama 700-8530, Japan
| | - Nobumasa Yakushiji
- Division of Pharmaceutical Sciences, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 1-1-1 Tsushima-Naka, Okayama 700-8530, Japan
| | - Ryosuke Shinozaki
- Division of Pharmaceutical Sciences, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 1-1-1 Tsushima-Naka, Okayama 700-8530, Japan
| | - Fuminori Ohsawa
- Division of Pharmaceutical Sciences, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 1-1-1 Tsushima-Naka, Okayama 700-8530, Japan
| | - Shoya Yamada
- Division of Pharmaceutical Sciences, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 1-1-1 Tsushima-Naka, Okayama 700-8530, Japan
| | - Yui Ohta
- Division of Pharmaceutical Sciences, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 1-1-1 Tsushima-Naka, Okayama 700-8530, Japan
| | - Kohei Kawata
- Division of Pharmaceutical Sciences, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 1-1-1 Tsushima-Naka, Okayama 700-8530, Japan
| | - Mariko Nakayama
- Division of Pharmaceutical Sciences, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 1-1-1 Tsushima-Naka, Okayama 700-8530, Japan
| | - Manabu Hagaya
- Division of Pharmaceutical Sciences, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 1-1-1 Tsushima-Naka, Okayama 700-8530, Japan
| | - Chisa Fujiwara
- Division of Pharmaceutical Sciences, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 1-1-1 Tsushima-Naka, Okayama 700-8530, Japan
| | - Makoto Makishima
- Division of Biochemistry, Department
of Biomedical Sciences, Nihon University School of Medicine, 30-1 Oyaguchi-kamicho, Itabashi-ku, Tokyo 173-8610, Japan
| | - Shigeyuki Uno
- Division of Biochemistry, Department
of Biomedical Sciences, Nihon University School of Medicine, 30-1 Oyaguchi-kamicho, Itabashi-ku, Tokyo 173-8610, Japan
| | - Akihiro Tai
- Faculty of Life and Environmental
Sciences, Prefectural University of Hiroshima, 562 Nanatsuka-Cho,
Shobara, Hiroshima 727-0023, Japan
| | - Ami Maehara
- Division of Medical Sciences, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikata-Cho, Kita-Ku, Okayama 700-8558,
Japan
| | - Masaru Nakayama
- Division of Medical Sciences, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikata-Cho, Kita-Ku, Okayama 700-8558,
Japan
| | - Toshitaka Oohashi
- Division of Medical Sciences, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikata-Cho, Kita-Ku, Okayama 700-8558,
Japan
| | - Hiroyuki Yasui
- Kyoto Pharmaceutical University, 5 Nakauchi-cho, Misasagi, Yamashina-ku,
Kyoto 607-8414, Japan
| | - Yutaka Yoshikawa
- Kyoto Pharmaceutical University, 5 Nakauchi-cho, Misasagi, Yamashina-ku,
Kyoto 607-8414, Japan
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24
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Zhao S, Li R, Li Y, Chen W, Zhang Y, Chen G. Roles of vitamin A status and retinoids in glucose and fatty acid metabolism. Biochem Cell Biol 2012; 90:142-52. [PMID: 22292422 DOI: 10.1139/o11-079] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The rising prevalence of metabolic diseases, such as obesity and diabetes, has become a public health concern. Vitamin A (VA, retinol) is an essential micronutrient for a variety of physiological processes, such as tissue differentiation, immunity, and vision. However, its role in glucose and lipid metabolism has not been clearly defined. VA activities are mediated by the metabolite of retinol catabolism, retinoic acid, which activates the retinoic acid receptor and retinoid X receptor (RXR). Since RXR is an obligate heterodimeric partner for many nuclear receptors involved in metabolism, it is reasonable to assume that VA status and retinoids contribute to glucose and lipid homeostasis. To date, the impacts of VA and retinoids on energy metabolism in animals and humans have been demonstrated in some basic and clinical investigations. This review summarizes the effects of VA status and retinoid treatments on metabolism of the liver, adipocytes, pancreatic β-cells, and skeletal muscle. It proposes a mechanism by which the dietary and hormonal signals converge on the promoter of sterol regulatory element-binding protein 1c gene to induce its expression, and in turn, the expression of lipogenic genes in hepatocytes. Future research projects relevant to the VA's roles in metabolic diseases are also discussed.
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Affiliation(s)
- Shi Zhao
- The Diabetes Center, Wuhan Central Hospital, Wuhan, Hubei 430014, China
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25
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Zhang Y, Zhang H, Yao XG, Shen H, Chen J, Li C, Chen L, Zheng M, Ye J, Hu L, Shen X, Jiang H. (+)-Rutamarin as a dual inducer of both GLUT4 translocation and expression efficiently ameliorates glucose homeostasis in insulin-resistant mice. PLoS One 2012; 7:e31811. [PMID: 22384078 PMCID: PMC3288053 DOI: 10.1371/journal.pone.0031811] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2011] [Accepted: 01/16/2012] [Indexed: 01/07/2023] Open
Abstract
Glucose transporter 4 (GLUT4) is a principal glucose transporter in response to insulin, and impaired translocation or decreased expression of GLUT4 is believed to be one of the major pathological features of type 2 diabetes mellitus (T2DM). Therefore, induction of GLUT4 translocation or/and expression is a promising strategy for anti-T2DM drug discovery. Here we report that the natural product (+)-Rutamarin (Rut) functions as an efficient dual inducer on both insulin-induced GLUT4 translocation and expression. Rut-treated 3T3-L1 adipocytes exhibit efficiently enhanced insulin-induced glucose uptake, while diet-induced obese (DIO) mice based assays further confirm the Rut-induced improvement of glucose homeostasis and insulin sensitivity in vivo. Subsequent investigation of Rut acting targets indicates that as a specific protein tyrosine phosphatase 1B (PTP1B) inhibitor Rut induces basal GLUT4 translocation to some extent and largely enhances insulin-induced GLUT4 translocation through PI3 kinase-AKT/PKB pathway, while as an agonist of retinoid X receptor α (RXRα), Rut potently increases GLUT4 expression. Furthermore, by using molecular modeling and crystallographic approaches, the possible binding modes of Rut to these two targets have been also determined at atomic levels. All our results have thus highlighted the potential of Rut as both a valuable lead compound for anti-T2DM drug discovery and a promising chemical probe for GLUT4 associated pathways exploration.
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Affiliation(s)
- Yu Zhang
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Haitao Zhang
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Xin-gang Yao
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Hong Shen
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Jing Chen
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Chenjing Li
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Lili Chen
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Mingyue Zheng
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Jiming Ye
- Molecular Pharmacology for Diabetes, School of Health Sciences, RMIT University, Melbourne, Victoria, Australia
| | - Lihong Hu
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
- * E-mail: (LH); (XS); (HJ)
| | - Xu Shen
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
- * E-mail: (LH); (XS); (HJ)
| | - Hualiang Jiang
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
- * E-mail: (LH); (XS); (HJ)
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Hosseini M, Ehrhardt N, Weissglas-Volkov D, Lai CM, Mao HZ, Liao JL, Nikkola E, Bensadoun A, Taskinen MR, Doolittle MH, Pajukanta P, Péterfy M. Transgenic expression and genetic variation of Lmf1 affect LPL activity in mice and humans. Arterioscler Thromb Vasc Biol 2012; 32:1204-10. [PMID: 22345169 DOI: 10.1161/atvbaha.112.245696] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
OBJECTIVE Lipoprotein lipase (LPL) is a principal enzyme in lipoprotein metabolism, tissue lipid utilization, and energy metabolism. LPL is synthesized by parenchymal cells in adipose, heart, and muscle tissues followed by secretion to extracellular sites, where lipolyic function is exerted. The catalytic activity of LPL is attained during posttranslational maturation, which involves glycosylation, folding, and subunit assembly within the endoplasmic reticulum. A lipase-chaperone, lipase maturation factor 1 (Lmf1), has recently emerged as a critical factor in this process. Previous studies demonstrated that loss-of-function mutations of Lmf1 result in diminished lipase activity and severe hypertriglyceridemia in mice and human subjects. The objective of this study is to investigate whether, beyond its role as a required factor in lipase maturation, variation in Lmf1 expression is sufficient to modulate LPL activity in vivo. METHODS AND RESULTS To assess the effects of Lmf1 overexpression in adipose and muscle tissues, we generated aP2-Lmf1 and Mck-Lmf1 transgenic mice. Characterization of relevant tissues revealed increased LPL activity in both mouse strains. In the omental and subcutaneous adipose depots, Lmf1 overexpression was associated with increased LPL specific activity without changes in LPL mass. In contrast, increased LPL activity was due to elevated LPL protein level in heart and gonadal adipose tissue. To extend these studies to humans, we detected association between LMF1 gene variants and postheparin LPL activity in a dyslipidemic cohort. CONCLUSIONS Our results suggest that variation in Lmf1 expression is a posttranslational determinant of LPL activity.
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Affiliation(s)
- Maryam Hosseini
- Medical Genetics Institute, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
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Hsieh CH, Pei D, Hung YJ, Hsiao FC. Association between retinoid-X receptor-gamma genetic polymorphisms and diabetic retinopathy. GENETICS AND MOLECULAR RESEARCH 2011; 10:3545-51. [PMID: 22180072 DOI: 10.4238/2011.december.5.4] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Retinoid-X receptor (RXR) is one of the members of the nuclear hormone receptor superfamily. It forms heterodimers with many nuclear receptors, such as the peroxisome proliferative-activated receptor, which has been proposed to be involved in diabetic complications, including retinopathy. A recent study revealed that RXR-alpha has antioxidant properties and is associated with diabetic retinopathy. We found that the RXR-gamma gene is involved in the pathogenesis of diabetic nephropathy. We also hypothesized that the RXR-gamma gene has a role in the development of diabetic retinopathy. We examined 213 diabetic patients, who were divided into retinopathy or no retinopathy groups. Nine selected single nucleotide polymorphisms (SNPs) in the RXR-gamma gene were evaluated. The diabetic retinopathy group had longer diabetes duration, higher body mass indexes, and higher systolic blood pressure, as well as higher concentrations of fasting plasma glucose, blood urine nitrogen, and creatine. One SNP--rs3818569 of the RXR-gamma gene was found to be associated with increased risk for diabetic retinopathy in both allele and genotype frequencies (P = 0.0023 and 0.0057, respectively). Analysis with multivariate logistic regression revealed that the dominant RXR-gamma GG genotype is a risk factors for the development of diabetic retinopathy (odds ratio = 2.388; 95% confidence interval = 1.17-4.875). We conclude that the RXR-gamma rs3818569 SNP is associated with diabetic retinopathy development in the Taiwanese population.
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Affiliation(s)
- C-H Hsieh
- Department of Internal Medicine, Division of Endocrinology and Metabolism, National Defense Medical Center, Tri-Service General Hospital, Taipei, Taiwan.
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Israeli S, Pessach Y, Sarig O, Goldberg I, Sprecher E. Beneficial effect of acitretin in Chanarin-Dorfman syndrome. Clin Exp Dermatol 2011; 37:31-3. [DOI: 10.1111/j.1365-2230.2011.04164.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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29
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Lipid metabolism in mammalian tissues and its control by retinoic acid. Biochim Biophys Acta Mol Cell Biol Lipids 2011; 1821:177-89. [PMID: 21669299 DOI: 10.1016/j.bbalip.2011.06.001] [Citation(s) in RCA: 146] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2011] [Revised: 05/10/2011] [Accepted: 06/01/2011] [Indexed: 12/18/2022]
Abstract
Evidence has accumulated that specific retinoids impact on developmental and biochemical processes influencing mammalian adiposity including adipogenesis, lipogenesis, adaptive thermogenesis, lipolysis and fatty acid oxidation in tissues. Treatment with retinoic acid, in particular, has been shown to reduce body fat and improve insulin sensitivity in lean and obese rodents by enhancing fat mobilization and energy utilization systemically, in tissues including brown and white adipose tissues, skeletal muscle and the liver. Nevertheless, controversial data have been reported, particularly regarding retinoids' effects on hepatic lipid and lipoprotein metabolism and blood lipid profile. Moreover, the molecular mechanisms underlying retinoid effects on lipid metabolism are complex and remain incompletely understood. Here, we present a brief overview of mammalian lipid metabolism and its control, introduce mechanisms through which retinoids can impact on lipid metabolism, and review reported activities of retinoids on different aspects of lipid metabolism in key tissues, focusing on retinoic acid. Possible implications of this knowledge in the context of the management of obesity and the metabolic syndrome are also addressed. This article is part of a Special Issue entitled Retinoid and Lipid Metabolism.
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KAKUTA H. Challenge of Creating Single-agents for the Treatment of Type 1 and 2 Diabetes by Targeting Retinoid X Receptor. YAKUGAKU ZASSHI 2011; 131:917-23. [DOI: 10.1248/yakushi.131.917] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Hiroki KAKUTA
- Okayama University, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences
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31
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Sugita S, Kamei Y, Akaike F, Suganami T, Kanai S, Hattori M, Manabe Y, Fujii N, Takai-Igarashi T, Tadaishi M, Oka JI, Aburatani H, Yamada T, Katagiri H, Kakehi S, Tamura Y, Kubo H, Nishida K, Miura S, Ezaki O, Ogawa Y. Increased systemic glucose tolerance with increased muscle glucose uptake in transgenic mice overexpressing RXRγ in skeletal muscle. PLoS One 2011; 6:e20467. [PMID: 21655215 PMCID: PMC3105070 DOI: 10.1371/journal.pone.0020467] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2011] [Accepted: 04/26/2011] [Indexed: 01/27/2023] Open
Abstract
Background Retinoid X receptor (RXR) γ is a nuclear receptor-type transcription
factor expressed mostly in skeletal muscle, and regulated by nutritional
conditions. Previously, we established transgenic mice overexpressing
RXRγ in skeletal muscle (RXRγ mice), which showed lower blood
glucose than the control mice. Here we investigated their glucose
metabolism. Methodology/Principal Findings RXRγ mice were subjected to glucose and insulin tolerance tests, and
glucose transporter expression levels, hyperinsulinemic-euglycemic clamp and
glucose uptake were analyzed. Microarray and bioinformatics analyses were
done. The glucose tolerance test revealed higher glucose disposal in
RXRγ mice than in control mice, but insulin tolerance test revealed no
difference in the insulin-induced hypoglycemic response. In the
hyperinsulinemic-euglycemic clamp study, the basal glucose disposal rate was
higher in RXRγ mice than in control mice, indicating an
insulin-independent increase in glucose uptake. There was no difference in
the rate of glucose infusion needed to maintain euglycemia (glucose infusion
rate) between the RXRγ and control mice, which is consistent with the
result of the insulin tolerance test. Skeletal muscle from RXRγ mice
showed increased Glut1 expression, with increased glucose uptake, in an
insulin-independent manner. Moreover, we performed in vivo
luciferase reporter analysis using Glut1 promoter
(Glut1-Luc). Combination of RXRγ and PPARδ
resulted in an increase in Glut1-Luc activity in skeletal
muscle in vivo. Microarray data showed that RXRγ
overexpression increased a diverse set of genes, including glucose
metabolism genes, whose promoter contained putative PPAR-binding motifs. Conclusions/Significance Systemic glucose metabolism was increased in transgenic mice overexpressing
RXRγ. The enhanced glucose tolerance in RXRγ mice may be mediated at
least in part by increased Glut1 in skeletal muscle. These results show the
importance of skeletal muscle gene regulation in systemic glucose
metabolism. Increasing RXRγ expression may be a novel therapeutic
strategy against type 2 diabetes.
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Affiliation(s)
- Satoshi Sugita
- Department of Molecular Medicine and
Metabolism, Medical Research Institute, Tokyo Medical and Dental University,
Tokyo, Japan
| | - Yasutomi Kamei
- Department of Molecular Medicine and
Metabolism, Medical Research Institute, Tokyo Medical and Dental University,
Tokyo, Japan
- * E-mail:
| | - Fumiko Akaike
- Department of Molecular Medicine and
Metabolism, Medical Research Institute, Tokyo Medical and Dental University,
Tokyo, Japan
- Laboratory of Pharmacology, Faculty of
Pharmaceutical Sciences, Tokyo University of Science, Chiba, Japan
| | - Takayoshi Suganami
- Department of Molecular Medicine and
Metabolism, Medical Research Institute, Tokyo Medical and Dental University,
Tokyo, Japan
| | - Sayaka Kanai
- Department of Molecular Medicine and
Metabolism, Medical Research Institute, Tokyo Medical and Dental University,
Tokyo, Japan
| | - Maki Hattori
- Department of Molecular Medicine and
Metabolism, Medical Research Institute, Tokyo Medical and Dental University,
Tokyo, Japan
- Laboratory of Pharmacology, Faculty of
Pharmaceutical Sciences, Tokyo University of Science, Chiba, Japan
| | - Yasuko Manabe
- Graduate School of Human Health Sciences,
Tokyo Metropolitan University, Tokyo, Japan
| | - Nobuharu Fujii
- Graduate School of Human Health Sciences,
Tokyo Metropolitan University, Tokyo, Japan
| | - Takako Takai-Igarashi
- Department of Bioinformatics, Graduate School
of Biomedical Science, Tokyo Medical and Dental University, Tokyo,
Japan
| | - Miki Tadaishi
- Nutritional Science Program, National
Institute of Health and Nutrition, Tokyo, Japan
- Department of Nutritional Science, Faculty of
Applied Bioscience, Tokyo University of Agriculture, Tokyo, Japan
| | - Jun-Ichiro Oka
- Laboratory of Pharmacology, Faculty of
Pharmaceutical Sciences, Tokyo University of Science, Chiba, Japan
| | - Hiroyuki Aburatani
- Research Center for Advanced Science and
Technology, University of Tokyo, Tokyo, Japan
| | - Tetsuya Yamada
- Department of Metabolic Diseases, Center for
Metabolic Diseases, Tohoku University Graduate School of Medicine, Miyagi,
Japan
| | - Hideki Katagiri
- Department of Metabolic Diseases, Center for
Metabolic Diseases, Tohoku University Graduate School of Medicine, Miyagi,
Japan
| | - Saori Kakehi
- Department of Medicine, Metabolism and
Endocrinology, School of Medicine, Juntendo University, Tokyo, Japan
| | - Yoshifumi Tamura
- Department of Medicine, Metabolism and
Endocrinology, School of Medicine, Juntendo University, Tokyo, Japan
- Sportology Center, Juntendo University,
Tokyo, Japan
| | | | | | - Shinji Miura
- Nutritional Science Program, National
Institute of Health and Nutrition, Tokyo, Japan
| | - Osamu Ezaki
- Nutritional Science Program, National
Institute of Health and Nutrition, Tokyo, Japan
| | - Yoshihiro Ogawa
- Department of Molecular Medicine and
Metabolism, Medical Research Institute, Tokyo Medical and Dental University,
Tokyo, Japan
- Global Center of Excellence Program,
International Research Center for Molecular Science in Tooth and Bone Diseases,
Medical Research Institute, Tokyo Medical and Dental University, Tokyo,
Japan
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Modulation of RXR function through ligand design. Biochim Biophys Acta Mol Cell Biol Lipids 2011; 1821:57-69. [PMID: 21515403 DOI: 10.1016/j.bbalip.2011.04.003] [Citation(s) in RCA: 124] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2011] [Revised: 04/06/2011] [Accepted: 04/07/2011] [Indexed: 12/22/2022]
Abstract
As the promiscuous partner of heterodimeric associations, retinoid X receptors (RXRs) play a key role within the Nuclear Receptor (NR) superfamily. Some of the heterodimers (PPAR/RXR, LXR/RXR, FXR/RXR) are "permissive" as they become transcriptionally active in the sole presence of either an RXR-selective ligand ("rexinoid") or a NR partner ligand. In contrast, "non-permissive" heterodimers (including RAR/RXR, VDR/RXR and TR/RXR) are unresponsive to rexinoids alone but these agonists superactivate transcription by synergizing with partner agonists. Despite their promiscuity in heterodimer formation and activation of multiple pathways, RXR is a target for drug discovery. Indeed, a rexinoid is used in the clinic for the treatment of cutaneous T-cell lymphoma. In addition to cancer RXR modulators hold therapeutical potential for the treatment of metabolic diseases. The modulation potential of the rexinoid (as agonist or antagonist ligand) is dictated by the precise conformation of the ligand-receptor complexes and the nature and extent of their interaction with co-regulators, which determine the specific physiological responses through transcription modulation of cognate gene networks. Notwithstanding the advances in this field, it is not yet possible to predict the correlation between ligand structure and physiological response. We will focus on this review on the modulation of PPARγ/RXR and LXR/RXR heterodimer activities by rexinoids. The genetic and pharmacological data from animal models of insulin resistance, diabetes and obesity demonstrate that RXR agonists and antagonists have promise as anti-obesity agents. However, the treatment with rexinoids raises triglycerides levels, suppresses the thyroid hormone axis, and induces hepatomegaly, which has complicated the development of these compounds as therapeutic agents for the treatment of type 2 diabetes and insulin resistance. The discovery of PPARγ/RXR and LXR/RXR heterodimer-selective rexinoids, which act differently than PPARγ or LXR agonists, might overcome some of these limitations.
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Ogasawara A, Murakami Y, Yakushiji N, Ohsawa F, Kusaba JI, Aiba T, Kurosaki Y, Kakuta H. Pharmacokinetic properties of newly synthesized retinoid X receptor agonists possessing a 6-[N-ethyl-N-(3-alkoxy-4-isopropylphenyl)amino]nicotinic acid skeleton in rats. Drug Dev Ind Pharm 2011; 37:1060-7. [PMID: 21417609 DOI: 10.3109/03639045.2011.559247] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVE The pharmacokinetic properties of three newly synthesized retinoid X receptor (RXR) agonists were evaluated in rats to elucidate the structural factor influencing their pharmacokinetic properties. MATERIAL AND METHODS Three RXR agonists possessing a common 6-[N-ethyl-N-(3-alkoxy-4-isopropylphenyl)amino]nicotinic acid skeleton and side chain structures that are slightly different from each other were prepared as we previously reported (Takamatsu et al., ChemMedChem, 2008; 3:780-787). The plasma concentration profiles of these compounds were evaluated following the intravenous and intra-intestinal administrations. Their hepatic metabolism was characterized using rat liver microsomes. RESULTS Based on the plasma concentration profile, NEt-3IP (3-isopropoxy) was shown to have a distribution volume of 4.53 L/kg, and to be cleared from the body with an elimination half-time of 0.95 h. The bioavailability of NEt-3IP is 16.4%, whereas those of the isobutoxy analog NEt-3IB and the cyclopropylmethoxy analog NEt-3cPM are 46.5% and 22.6%, respectively. Subsequently, in the experiments using rat liver microsomes, the K(m) and V(max) values of NEt-3IP were determined as 7.85 µM and 0.48 nmol/min/mg protein, respectively. This K(m) value is nearly the same as those of NEt-3IB and NEt-3cPM, but the V(max) value is noticeably smaller. Additionally, it was revealed that the CYP family mainly metabolizing NEt-3IP is different from those metabolizing the other analogs. CONCLUSION Based on these findings, the pharmacokinetic properties of the compounds possessing this type of the skeleton seem to be largely influenced by a slight modification of the side chain structure.
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Affiliation(s)
- Akemi Ogasawara
- Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
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Ohsawa F, Morishita KI, Yamada S, Makishima M, Kakuta H. Modification at the Lipophilic Domain of RXR Agonists Differentially Influences Activation of RXR Heterodimers. ACS Med Chem Lett 2010; 1:521-5. [PMID: 24900241 DOI: 10.1021/ml100184k] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2010] [Accepted: 08/24/2010] [Indexed: 02/02/2023] Open
Abstract
RXR permissive heterodimers are reported to be activated differently depending upon the chemical structure of RXR agonists, but the relationship of agonist structure to differential heterodimer activation has not been explored in detail. In this study, we performed systematic conversion of the alkoxy side chain of 5a (6-[ethyl-(3-isopropoxy-4-isopropylphenyl)amino]nicotinic acid, NEt-3IP) and evaluated the RXR-, PPAR/RXR-, and LXR/RXR-agonist activities of the products. The cyclopropylmethoxy analogue (5c) showed similar RXR- and LXR/RXR-agonistic activities to the benzyloxy analogue (5i) and n-propoxy analogue (5k) but exhibited more potent PPAR/RXR-agonistic activity than 5i or 5k. Differential modulation of RXR heterodimer-activating ability by conversion of the alkoxy group located in the lipophilic domain of the RXR-agonist common structure is expected be a useful approach in the design of new RXR agonists for the treatment of hyperlipidemia or type 2 diabetes.
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Affiliation(s)
- Fuminori Ohsawa
- Division of Pharmaceutical Sciences, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 1-1-1, Tsushima-Naka, Kita-Ku, Okayama 700-8530, Japan
- Multiple Molecular Imaging Research Laboratory, RIKEN Center for Molecular Imaging Science, Minatojima-minamimachi 6-7-3, Chuo-ku, Kobe, Hyogo 650-0047, Japan
| | - Ken-ichi Morishita
- Division of Pharmaceutical Sciences, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 1-1-1, Tsushima-Naka, Kita-Ku, Okayama 700-8530, Japan
| | - Shoya Yamada
- Division of Pharmaceutical Sciences, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 1-1-1, Tsushima-Naka, Kita-Ku, Okayama 700-8530, Japan
| | - Makoto Makishima
- Division of Biochemistry, Nihon University School of Medicine, Itabashi-Ku, Tokyo 173-8610, Japan
| | - Hiroki Kakuta
- Division of Pharmaceutical Sciences, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 1-1-1, Tsushima-Naka, Kita-Ku, Okayama 700-8530, Japan
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Modification at the acidic domain of RXR agonists has little effect on permissive RXR-heterodimer activation. Bioorg Med Chem Lett 2010; 20:5139-42. [DOI: 10.1016/j.bmcl.2010.07.012] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2010] [Revised: 06/25/2010] [Accepted: 07/06/2010] [Indexed: 11/22/2022]
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Preitner F, Mody N, Graham TE, Peroni OD, Kahn BB. Long-term Fenretinide treatment prevents high-fat diet-induced obesity, insulin resistance, and hepatic steatosis. Am J Physiol Endocrinol Metab 2009; 297:E1420-9. [PMID: 19826103 PMCID: PMC2793052 DOI: 10.1152/ajpendo.00362.2009] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The synthetic retinoid Fenretinide (FEN) increases insulin sensitivity in obese rodents and is in early clinical trials for treatment of insulin resistance in obese humans with hepatic steatosis (46). We aimed to determine the physiological mechanisms for the insulin-sensitizing effects of FEN. Wild-type mice were fed a high-fat diet (HFD) with or without FEN from 4-5 wk to 36-37 wk of age (preventive study) or following 22 wk of HF diet-induced obesity (12 wk intervention study). Retinol-binding protein-4 (RBP4) knockout mice were also fed the HFD with or without FEN in a preventive study. FEN had minimal effects on HFD-induced body weight gain but markedly reduced HFD-induced adiposity and hyperleptinemia in both studies. FEN-HFD mice gained epididymal fat but not subcutaneous or visceral fat mass in contrast to HFD mice without FEN. FEN did not have a measurable effect on energy expenditure, food intake, physical activity, or stool lipid content. Glucose infusion rate during hyperinsulinemic-euglycemic clamp was reduced 86% in HFD mice compared with controls and was improved 3.6-fold in FEN-HFD compared with HFD mice. FEN improved insulin action on glucose uptake and glycogen levels in muscle, insulin-stimulated suppression of hepatic glucose production, and suppression of serum FFA levels in HFD mice. Remarkably, FEN also reduced hepatic steatosis. In RBP4 knockout mice, FEN reduced the HFD-induced increase in adiposity and hyperleptinemia. In conclusion, long-term therapy with FEN partially prevents or reverses obesity, insulin resistance, and hepatic steatosis in mice on HFD. The anti-adiposity effects are independent of the RBP4 lowering effect.
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Affiliation(s)
- Frederic Preitner
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA
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Nohara A, Kobayashi J, Mabuchi H. Retinoid X receptor heterodimer variants and cardiovascular risk factors. J Atheroscler Thromb 2009; 16:303-18. [PMID: 19672026 DOI: 10.5551/jat.no786] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Nuclear receptors are transcription factors that can be activated by specific ligands. Recent progress has shown that retinoid X receptor (RXR) and its heterodimerization partners, including peroxisome proliferator-activated receptors, regulate many important genes involved in energy homeostasis and atherosclerosis, and should be promising therapeutic targets of metabolic syndrome. RXR heterodimers regulate a number of complex cellular processes, and genetic studies of RXR heterodimers have provided important clinical information in addition to knowledge gained from basic research. Genetic variants of RXR heterodimers were screened and investigated, and some variants were shown to have a considerable impact on metabolic disorders, including phenotypic components of familial combined hyperlipidemia. The combined efforts of basic and clinical science regarding nuclear receptors have achieved significant progress in unraveling the inextricably linked control system of energy expenditure, lipid and glucose homeostasis, inflammation, and atherosclerosis.This review summarizes the current understanding regarding RXR heterodimers based on their human genetic variants, which will provide new clues to uncover the background of multifactorial disease, such as metabolic syndrome or familial combined hyperlipidemia.
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Affiliation(s)
- Atsushi Nohara
- Departments of Lipidology, Kanazawa University Graduate School of Medical Science, Kanazawa, Japan.
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Abstract
Lipoprotein lipase (LPL) is a multifunctional enzyme produced by many tissues, including adipose tissue, cardiac and skeletal muscle, islets, and macrophages. LPL is the rate-limiting enzyme for the hydrolysis of the triglyceride (TG) core of circulating TG-rich lipoproteins, chylomicrons, and very low-density lipoproteins (VLDL). LPL-catalyzed reaction products, fatty acids, and monoacylglycerol are in part taken up by the tissues locally and processed differentially; e.g., they are stored as neutral lipids in adipose tissue, oxidized, or stored in skeletal and cardiac muscle or as cholesteryl ester and TG in macrophages. LPL is regulated at transcriptional, posttranscriptional, and posttranslational levels in a tissue-specific manner. Nutrient states and hormonal levels all have divergent effects on the regulation of LPL, and a variety of proteins that interact with LPL to regulate its tissue-specific activity have also been identified. To examine this divergent regulation further, transgenic and knockout murine models of tissue-specific LPL expression have been developed. Mice with overexpression of LPL in skeletal muscle accumulate TG in muscle, develop insulin resistance, are protected from excessive weight gain, and increase their metabolic rate in the cold. Mice with LPL deletion in skeletal muscle have reduced TG accumulation and increased insulin action on glucose transport in muscle. Ultimately, this leads to increased lipid partitioning to other tissues, insulin resistance, and obesity. Mice with LPL deletion in the heart develop hypertriglyceridemia and cardiac dysfunction. The fact that the heart depends increasingly on glucose implies that free fatty acids are not a sufficient fuel for optimal cardiac function. Overall, LPL is a fascinating enzyme that contributes in a pronounced way to normal lipoprotein metabolism, tissue-specific substrate delivery and utilization, and the many aspects of obesity and other metabolic disorders that relate to energy balance, insulin action, and body weight regulation.
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Affiliation(s)
- Hong Wang
- Division of Endocrinology, Metabolism and Diabetes, University of Colorado Denver Anschutz Medical Campus, Aurora, Colorado 80045, USA
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Lalloyer F, Pedersen TA, Gross B, Lestavel S, Yous S, Vallez E, Gustafsson JA, Mandrup S, Fiévet C, Staels B, Tailleux A. Rexinoid bexarotene modulates triglyceride but not cholesterol metabolism via gene-specific permissivity of the RXR/LXR heterodimer in the liver. Arterioscler Thromb Vasc Biol 2009; 29:1488-95. [PMID: 19592467 DOI: 10.1161/atvbaha.109.189506] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Bexarotene (Targretin) is a clinically used antitumoral agent which exerts its action through binding to and activation of the retinoid-X-receptor (RXR). The most frequent side-effect of bexarotene administration is an increase in plasma triglycerides, an independent risk factor of cardiovascular disease. The molecular mechanism behind this hypertriglyceridemia remains poorly understood. METHODS AND RESULTS Using wild-type and LXR alpha/beta-deficient mice, we show here that bexarotene induces hypertriglyceridemia and activates hepatic LXR-target genes of lipogenesis in an LXR-dependent manner, hence exerting a permissive effect on RXR/LXR heterodimers. Interestingly, RNA analysis and Chromatin Immunoprecipitation assays performed in the liver reveal that the in vivo permissive effect of bexarotene on the RXR/LXR heterodimer is restricted to lipogenic genes without modulation of genes controlling cholesterol homeostasis. CONCLUSIONS These findings demonstrate that the hypertriglyceridemic action of bexarotene occurs via the RXR/LXR heterodimer and show that RXR heterodimers can act with a selective permissivity on target genes of specific metabolic pathways in the liver.
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Vitamin A regulates obesity in WNIN/Ob obese rat; independent of stearoyl-CoA desaturase-1. Biochem Biophys Res Commun 2008; 370:243-7. [DOI: 10.1016/j.bbrc.2008.03.073] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2008] [Accepted: 03/16/2008] [Indexed: 01/08/2023]
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41
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Meissburger B, Wolfrum C. The role of retinoids and their receptors in metabolic disorders. EUR J LIPID SCI TECH 2008. [DOI: 10.1002/ejlt.200700291] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Altucci L, Leibowitz MD, Ogilvie KM, de Lera AR, Gronemeyer H. RAR and RXR modulation in cancer and metabolic disease. Nat Rev Drug Discov 2007; 6:793-810. [PMID: 17906642 DOI: 10.1038/nrd2397] [Citation(s) in RCA: 393] [Impact Index Per Article: 23.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Retinoic acid receptors (RARs) are ligand-controlled transcription factors that function as heterodimers with retinoid X receptors (RXRs) to regulate cell growth and survival. The success of RAR modulation in the treatment of acute promyelocytic leukaemia (APL) has stimulated considerable interest in the development of RAR and RXR modulators. This has been aided by recent advances in the understanding of the biological role of RARs and RXRs and in the design of selective receptor modulators that might overcome the limitations of current drugs. Here, we discuss the challenges and opportunities for therapeutic strategies based on RXR and RAR modulators, with a focus on cancer and metabolic diseases such as diabetes and obesity.
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Affiliation(s)
- Lucia Altucci
- Dipartimento di Patologia Generale, Seconda Università degli Studi di Napoli, Vico Luigi de Crecchio 7, 80138 Napoli, Italy
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Wu G, Zhang L, Gupta J, Olivecrona G, Olivecrona T. A transcription-dependent mechanism, akin to that in adipose tissue, modulates lipoprotein lipase activity in rat heart. Am J Physiol Endocrinol Metab 2007; 293:E908-15. [PMID: 17595214 DOI: 10.1152/ajpendo.00634.2006] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The enzyme lipoprotein lipase (LPL) releases fatty acids from lipoprotein triglycerides for use in cell metabolism. LPL activity is rapidly modulated in a tissue-specific manner. Recent studies have shown that in rat adipose tissue this occurs by a shift of extracellular LPL toward an inactive form catalyzed by an LPL-controlling protein whose expression changes in response to the nutritional state. To explore whether a similar mechanism operates in other tissues we injected actinomycin D to block transcription of the putative LPL controlling protein(s). When actinomycin was given to fed rats, heparin-releasable LPL activity increased by 160% in heart and by 150% in a skeletal muscle (soleus) in 6 h. Postheparin LPL activity in blood increased by about 200%. To assess the state of extracellular LPL we subjected the spontaneously released LPL in heart perfusates to chromatography on heparin-agarose, which separates the active and inactive forms of the lipase. The amount of lipase protein released remained relatively constant on changes in the nutritional state and/or blockade of transcription, but the distribution between the active and inactive forms changed. Less of the LPL protein was in the active form in perfusates from hearts from fed compared with fasted rats. When glucose was given to fasted rats the proportion of LPL protein in the active form decreased. Actinomycin D increased the proportion that was active, in accord with the hypothesis that the message for a rapidly turning over LPL-controlling protein was being removed.
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Affiliation(s)
- Gengshu Wu
- Department of Medical Biosciences, Physiological Chemistry, Umeå University, Umeå, Sweden
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Vahlquist A. Retinoid-Induced Hyperlipidemia and the Risk of Atherosclerosis. BASIC AND CLINICAL DERMATOLOGY 2007. [DOI: 10.3109/9781420021189.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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Nohara A, Kawashiri MA, Claudel T, Mizuno M, Tsuchida M, Takata M, Katsuda S, Miwa K, Inazu A, Kuipers F, Kobayashi J, Koizumi J, Yamagishi M, Mabuchi H. High Frequency of a Retinoid X Receptor γ Gene Variant in Familial Combined Hyperlipidemia That Associates With Atherogenic Dyslipidemia. Arterioscler Thromb Vasc Biol 2007; 27:923-8. [PMID: 17272748 DOI: 10.1161/01.atv.0000258945.76141.8a] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE The genetic background of familial combined hyperlipidemia (FCHL) has not been fully clarified. Because several nuclear receptors play pivotal roles in lipid metabolism, we tested the hypothesis that genetic variants of nuclear receptors contribute to FCHL. METHODS AND RESULTS We screened all the coding regions of the PPARalpha, PPARgamma2, PPARdelta, FXR, LXRalpha, and RXRgamma genes in 180 hyperlipidemic patients including 60 FCHL probands. Clinical characteristics of the identified variants were evaluated in other 175 patients suspected of coronary disease. We identified PPARalpha Asp140Asn and Gly395Glu, PPARgamma2 Pro12Ala, RXRgamma Gly14Ser, and FXR -1g->t variants. Only RXRgamma Ser14 was more frequent in FCHL (15%, P<0.05) than in other primary hyperlipidemia (4%) and in controls (5%). Among patients suspected of coronary disease, we identified 9 RXRgamma Ser14 carriers, who showed increased triglycerides (1.62+/-0.82 versus 1.91+/-0.42 [mean+/-SD] mmol/L, P<0.05), decreased HDL-cholesterol (1.32+/-0.41 versus 1.04+/-0.26, P<0.05), and decreased post-heparin plasma lipoprotein lipase protein levels (222+/-85 versus 149+/-38 ng/mL, P<0.01). In vitro, RXRgamma Ser14 showed significantly stronger repression of the lipoprotein lipase promoter than RXRgamma Gly14. CONCLUSION These findings suggest that RXRgamma contributes to the genetic background of FCHL.
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Affiliation(s)
- Atsushi Nohara
- Department of Lipidology, Graduate School of Medical Science, Kanazawa University, Takara-machi 13-1, Kanazawa 920-8641, Japan.
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Pinaire JA, Reifel-Miller A. Therapeutic potential of retinoid x receptor modulators for the treatment of the metabolic syndrome. PPAR Res 2007; 2007:94156. [PMID: 17497022 PMCID: PMC1852898 DOI: 10.1155/2007/94156] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2006] [Revised: 01/04/2007] [Accepted: 01/04/2007] [Indexed: 01/30/2023] Open
Abstract
The increasing prevalence of obesity is a fundamental contributor
to the growing prevalence of the metabolic syndrome. Rexinoids, a
class of compounds that selectively bind and activate RXR,
are being studied as a potential option for the treatment of
metabolic syndrome. These compounds have glucose-lowering,
insulin-sensitizing, and antiobesity effects in animal models
of insulin resistance and type 2 diabetes. However,
undesirable side effects such as hypertriglyceridemia and
suppression of the thyroid hormone axis also occur.
This review examines and compares the effects of four RXR-selective
ligands: LGD1069, LG100268, AGN194204, and LG101506, a selective
RXR modulator. Similar to selective modulators of other nuclear
receptors such as the estrogen receptor (SERMs), LG101506
binding to RXR selectively maintains the desirable characteristic
effects of rexinoids while minimizing the undesirable effects.
These recent findings suggest that, with continued research efforts,
RXR-specific ligands with improved pharmacological profiles may
eventually be available as additional treatment options for the
current epidemic of obesity, insulin resistance, type 2 diabetes,
and all of the associated metabolic sequelae.
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Affiliation(s)
- Jane A. Pinaire
- Lilly Research Laboratories, Lilly Corporate Center, Indianapolis, IN 46285, USA
- *Jane A. Pinaire:
| | - Anne Reifel-Miller
- Lilly Research Laboratories, Lilly Corporate Center, Indianapolis, IN 46285, USA
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Golden WM, Weber KB, Hernandez TL, Sherman SI, Woodmansee WW, Haugen BR. Single-dose rexinoid rapidly and specifically suppresses serum thyrotropin in normal subjects. J Clin Endocrinol Metab 2007; 92:124-30. [PMID: 17062760 DOI: 10.1210/jc.2006-0696] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
CONTEXT Retinoid X receptor agonists (rexinoids) have demonstrated benefit in patients with certain malignancies but appear to cause central hypothyroidism in some patients with advanced cancer. The influence of rexinoids on thyroid function in healthy subjects is not clear. OBJECTIVE The objective of this study was to determine the effect of a single dose of bexarotene on levels of TSH, T4, and T3 in healthy subjects. DESIGN This study was a randomized, double-blind, placebo-controlled, crossover trial. SETTING This study was conducted at the General Clinical Research Center (University of Colorado Health Sciences Center, Aurora, CO). SUBJECTS Six healthy adults (>18 yr old) were studied. INTERVENTION Single-dose rexinoid (bexarotene, 400 mg/m2) or placebo, with TSH measurements at 0, 1, 2, 4, 8, 12, 24, and 48 h, were used. MAIN OUTCOME MEASURE The main outcome was the serum TSH level at 24 h. RESULTS Single-dose bexarotene suppressed serum TSH (P < 0.001) over time. Compared with placebo, levels of TSH were significantly lower by 12 h (P = 0.043); the nadir of 0.32 +/- 0.02 mU/liter (P < 0.001) was seen at 24 h. Free T4 index and free T3 index were also significantly lower than placebo over time (48 h) (P = 0.029; P = 0.004, respectively). Serum prolactin, cortisol, and triglycerides were not affected (P > 0.05 for all). There was no significant effect of single-dose bexarotene on rT3 or T3/rT3 ratio at 24 h. CONCLUSION A single dose of a rexinoid can rapidly and specifically suppress serum TSH levels in healthy subjects. These data provide insight into the mechanisms by which rexinoids cause central hypothyroidism and potential ways this effect can be used for treatment of disorders such as thyroid hormone resistance and TSH-secreting pituitary tumors.
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Affiliation(s)
- Wendy M Golden
- Division of Endocrinology, Metabolism, and Diabetes, University of Colorado at Denver and Health Sciences Center, Building RC-1 South Tower, MS 8106; 12801 East 17th Avenue, PO Box 6511, Aurora, Colorado 80045, USA
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Abstract
Vitamin A signaling occurs through nuclear receptors recognizing diverse forms of retinoic acid (RA). The retinoic acid receptors (RARs) bind all-trans RA and its 9-cis isomer (9-cis RA). They convey most of the activity of RA, particularly during embryogenesis. The second subset of receptors, the rexinoid receptors (RXRs), binds 9-cis RA only. However, RXRs are obligatory DNA-binding partners for a number of nuclear receptors, broadening the spectrum of their biological activity to the corresponding nuclear receptor-signaling pathways. The present chapter more particularly focuses on RXR-containing transcriptional complexes for which RXR is not only a structural component necessary for DNA binding but also acts as a ligand-activated partner. After positioning RXR among the nuclear receptor superfamily in the first part, we will give an overview of three major signaling pathways involved in metabolism, which are sensitive to RXR activation: LXR:RXR, FXR:RXR, and PPAR:RXR. The third and last part is focused on RXR signaling and its potential role in metabolic regulation. Indeed, while the nature of the endogenous ligand for RXR is still in question, as we will discuss herein, a better understanding of RXR activities is necessary to envisage the potential therapeutic applications of synthetic RXR ligands.
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Affiliation(s)
- Béatrice Desvergne
- Center for Integrative Genomics, Building Génopode, University of Lausanne, CH-1015 Lausanne, Switzerland
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Li X, Hansen PA, Xi L, Chandraratna RAS, Burant CF. Distinct Mechanisms of Glucose Lowering by Specific Agonists for Peroxisomal Proliferator Activated Receptor γ and Retinoic Acid X Receptors. J Biol Chem 2005; 280:38317-27. [PMID: 16179348 DOI: 10.1074/jbc.m505853200] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Agonists for the nuclear receptor peroxisomal proliferator-activated receptor-gamma (PPARgamma) and its heterodimeric partner, retinoid X receptor (RXR), are effective agents for the treatment of type 2 diabetes. To gain insight into the antidiabetic action of these compounds, we treated female Zucker diabetic rats (ZFF) with AGN194204, which we show to be a homodimer-specific RXR agonist, or the PPARgamma agonist, troglitazone. Hyperinsulinemic-euglycemic clamps in ZFF showed that troglitazone and AGN194204 reduced basal endogenous glucose production (EGP) approximately 30% and doubled the insulin suppression of EGP. AGN194204 had no effect on peripheral glucose utilization, whereas troglitazone increased insulin-stimulated glucose utilization by 50%, glucose uptake into skeletal muscle by 85%, and de novo skeletal muscle glycogen synthesis by 300%. Troglitazone increased skeletal muscle Irs-1 and phospho-Akt levels following in vivo insulin treatment, whereas AGN194204 increased hepatic Irs-2 and insulin stimulated phospho-Akt in liver. Gene profiles of AGN194204-treated mouse liver analyzed by Ingenuity Pathway Analysis identified increases in fatty acid synthetic genes, including Srebp-1 and fatty acid synthase, a pathway previously shown to be induced by RXR agonists. A network of down-regulated genes containing Foxa2, Foxa3, and G-protein subunits was identified, and decreases in these mRNA levels were confirmed by quantitative reverse transcription-PCR. Treatment of HepG2 cells with AGN194204 resulted in inhibition of glucagon-stimulated cAMP accumulation suggesting the G-protein down-regulation may provide an additional mechanism for hepatic insulin sensitization by RXR. These studies demonstrate distinct molecular events lead to insulin sensitization by high affinity RXR and PPARgamma agonists.
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Affiliation(s)
- Xiangquan Li
- Division of Endocrinology and Metabolism, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan 48109-0354, USA
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50
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Szanto A, Narkar V, Shen Q, Uray IP, Davies PJA, Nagy L. Retinoid X receptors: X-ploring their (patho)physiological functions. Cell Death Differ 2005; 11 Suppl 2:S126-43. [PMID: 15608692 DOI: 10.1038/sj.cdd.4401533] [Citation(s) in RCA: 202] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Retinoid X receptor (RXR) belongs to a family of ligand-activated transcription factors that regulate many aspects of metazoan life. A class of nuclear receptors requires RXR as heterodimerization partner for their function. This places RXR in the crossroad of multiple distinct biological pathways. This and the fact that the debate on the endogenous ligand requirement for RXR is not yet settled make RXR still an enigmatic transcription factor. Here, we review some of the biology of RXR. We place RXR into the evolution of nuclear receptors, review structural details and ligands of the receptor. Then processes regulated by RXR are discussed focusing on the developmental roles deduced from studies on knockout animals and metabolic roles in diseases such as diabetes and atherosclerosis deduced from pharmacological studies. Finally, aspects of RXR's involvement in myeloid differentiation and apoptosis are summarized along with issues on RXR's suitability as a therapeutic target.
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Affiliation(s)
- A Szanto
- Department of Biochemistry and Molecular Biology, Research Center for Molecular Medicine, University of Debrecen, Nagyerdei krt. 98, Debrecen H-4012, Hungary
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